A researcher wishes to​ estimate, with 99​% ​confidence, the population proportion of adults who support labeling legislation for genetically modified organisms​ (GMOs). Her estimate must be accurate within 2​% of the true proportion.   ​(a) No preliminary estimate is available. Find the minimum sample size needed. ​(b) Find the minimum sample size​ needed, using a prior study that found that 79​% of the respondents said they support labeling legislation for GMOs. ​(c) Compare the results from parts​ (a) and​ (b).

A researcher wishes to​ estimate, with 90​% confidence, the population proportion of adults who support labeling legislation for genetically modified organisms​ (GMOs). Her estimate must be accurate within 5​% of the true proportion. ​(a) No preliminary estimate is available. Find the minimum sample size needed. ​(b) Find the minimum sample size​ needed, using a prior study that found that 69​% of the respondents said they support labeling legislation for GMOs. ​(c) Compare the results from parts​ (a) and​ (b).

The state education commission wants to estimate the fraction of tenth grade students that have reading skills at or below the eighth grade level.  Suppose a sample of 2552 tenth graders is drawn. Of the students sampled, 2119 read above the eighth grade level. Using the data, estimate the proportion of tenth graders reading at or below the eighth grade level. Enter your answer as a fraction or a decimal number rounded to three decimal places.

A local nursery specializes in custom-designed landscaping for residential areas. The estimated labor cost associated with a particular landscaping proposal is based on the number of plantings of trees, shrubs, and so on to be used for the project. For cost-estimating purposes, managers use 2.2 hours of labor time for planting of a medium-sized tree. A random sample of 36 tree plantings is selected and the planting times are recorded. The average planting time for the sample of 36 planting is 2.7 hours with a standard deviation of .9 hours. The researcher wants to test if the average planting time is significantly greater than 2.2 hours based on the data that was collected. Họ: H= 2.2 H1: u> 2.2 What is the value of the Test Statistic for this hypothesis test? Round Z to the 100ths place.

You have been asked to estimate the proportion of households in Chicago that have two or more vehicles.   a) How many households would you need to sample to be within 2 percent of the proportion of all households in Chicago that have two or more vehicles at a 90% level of confidence.     b) You conduct a small preliminary sample, and you obtain a sample proportion of 19.5% that have two or more cars. Using this new information, what sample size should you gather in order to be within 2 percent of the proportion of all households in Chicago that have two or more vehicles at a 90% level of confidence.

A researcher wishes to estimate, with 99% confidence, the population proportion of adults who support labeling legislation for genetically modified organisms (GMOs). Her estimate must be accurate within 5% of the true proportion. (a) No preliminary estimate is available. Find the minimum sample size needed. (b) Find the minimum sample size needed, using a prior study that found that 79% of the respondents said they support labeling legislation for GMOs. (c) Compare the results from parts (a) and (b). (a) What is the minimum sample size needed assuming that no prior information is available?

Calculate the margin of error. What does the article state as the margin of error?

A researcher wants to determine the percentage of American teenagers who send or receive text messages while doing homework. Which of the following techniques would likely be the MOST efficient way of obtaining an accurate estimate for this percentage? 1. Randomly select teenagers from the list of all teenage students in every state in America and mail surveys to those teens, asking them if they send or receive text messages while doing homework. 2. Send a survey to every teenager in America and ask them if they send or receive text messages while doing homework. 3. Randomly select teenagers from the list of all teenage students in one state and mail surveys to those teens, asking them if they send or receive text messages while doing homework.

A programmer plans to develop a new software system. In planning for the operating system that he will​ use, he needs to estimate the percentage of computers that use a new operating system. How many computers must be surveyed in order to be 99​% confident that his estimate is in error by no more than three percentage points? Complete parts​ (a) through​ (c) below.       Question content area bottom Part 1 ​a) Assume that nothing is known about the percentage of computers with new operating systems.   n=enter your response here ​(Round up to the nearest​ integer.) Part 2 ​b) Assume that a recent survey suggests that about 90​% of computers use a new operating system.   n=enter your response here ​(Round up to the nearest​ integer.) Part 3

You have been asked to estimate the proportion of households in Chicago that have two or more vehicles.   a) How many households would you need to sample to be within 1.5 percent of the proportion of all households in Chicago that have two or more vehicles at a 95% level of confidence.     b) You conduct a small preliminary sample, and you obtain a sample proportion of 20% that have two or more cars. Using this new information, what sample size should you gather in order to be within 1.5 percent of the proportion of all households in Chicago that have two or more vehicles at a 95% level of confidence.